The Development of Alcoholic Subtypes: Risk Variation Among Alcoholic Families During the Early Childhood Years.

Lifetime differences in antisocial behavior among alcoholic men historically have been useful in distinguishing alcoholic subtypes. However, the usefulness of this subtyping strategy for identifying differences in families that may put offspring at risk for developing later alcoholism has not been previously documented. Findings from a prospective study on the development of vulnerability for alcoholism among (initially) preschool-age children showed that children from families with antisocial alcoholism differ on a number of indicators of child risk, including measures of risky temperament, externalizing behavior problems, and hyperactivity. Risk differences among children from these family subtypes appear to be sustained into middle childhood. Differences between nonantisocial alcoholic families and nonalcoholic control families were less distinguishable in both early and middle childhood.

this pattern of behavior over time (Skog and Duckert l993).Because such het erogeneity exists within this classifi cation system, scientists continue to speculate that the causes underlying the apparently single disorder of alco hol abusedependence may actually involve multiple processes (Cloninger l987;Cloninger et al. l986;Hesselbrock l995;Schuckit l985;Zucker l994).Sci entists continue to look for other cate gorization approaches that would better reflect the variability that exists within the alcohol abusedependence frame work.This is the rationale behind the search for subtypes.
One study that has documented the heterogeneity found within alcohol abuse and dependence is the Epidemi ologic Catchment Area (ECA) Study.This study provided a survey of the distribution of psychiatric disorders.Using these data, scientists have been able to project the prevalence of alco hol abusedependence within the U.S. population as well as begin to make estimates of the extent to which this disorder is associated (i.e., the degree ROBERT A. ZUCKER, PH.D.,  of aggregation) with other psychiatric syndromes, such as antisocial person ality disorder (ASPD) (Helzer and Pryzbeck l988; Regier et al. l990).The ECA study has documented that significant variation exists in the de gree of aggregation of alcohol abuse dependence with other psychiatric disorders.For example, although ASPD occurs in only 4 percent of the U.S. male noninstitutional population, it is 12 times more common among those with alcohol abusedependence than it is among those without the alcohol use disorder.Less dramatic, but also suggestive of aggregation, is the asso ciation, particularly in women, between mania and alcohol abusedependence.Mania occurs in less than 1 percent of the general population of women; how ever, the chances of depression being present are nine times greater among woman with alcohol abusedependence.These aforementioned associations may be possible indicators of differ ent alcoholdisorder subtypes (Babor and Dolinsky l988;Zucker l994).If this is the case, the comorbid psychiatric disorders would help in identifying alcoholism1 subtypes that are clinically more alike (i.e., homogeneous).
Several possible theories exist to ex plain how alcohol abusedependence may be linked to other psychiatric dis orders.One hypothesis states that be cause alcohol abusedependence and other disorders occur together, these disorders must share a common devel opmental process (i.e., etiology).An alternative possibility, and one that must be ruled out to fully understand the cooccurrence of these disorders, is that the psychiatric symptoms are simply a result of the alcoholism, rather than a marker of a common causal process.Still another possibility is that the symptoms of alcoholism and other psychiatric disorders occur indepen dently but share a common factor that contributes to the development of both disorders. 2By determining how alco holism relates to psychiatric symptoms, researchers may be able to determine which explanation is the most likely.Researchers would then come closer to identifying the subtypes that best reflect the heterogeneity of the disor der.Such specific descriptions would be useful as indicators of potential dif ferences in the course and causes of the disorder and could possibly assist in the development of prevention and treatment strategies.
In both men and women, alcohol ism is associated most strongly with the comorbid disorder ASPD.This disorder is characterized by a pervasive disregard for and violation of the rights of others and is evident during both childhood and adulthood.The presence or absence of symptoms composing ASPD is a major distinguishing feature of virtually all of the alcoholism sub typing schemes developed during the past generation (Babor and Dolinsky l988;Cloninger et al. l981;Hesselbrock et al. l984;Babor et al. l992;Zucker l994;Zucker et al. 1994).Although it is less commonly acknowledged, children from families with alcoholic adults who have antisocial symptoms (i.e., who have high levels of antisocial symptomatology) are at greater risk of becoming alcoholic later in life than other children.(For a definition of risk, see sidebar.)The risk factors in clude having a greater number of al coholic relatives (i.e., a denser family history of alcoholism), which, in turn, will increase the probability that the Because this alternative ultimately ties back to a com mon causal process for both disorders and thus would contribute to understanding subtypes and their out comes, it can be considered a variant of the first alter native described.

A NOTE ABOUT LIFECOURSE VARIATION AND THE DEVELOPMENT OF RISK
The concept of risk refers to the statisti cal probability that a specific (usually negative) outcome will occur at a later date (Zucker l989).Thus, when identi fying risk characteristics for the later emergence of alcoholism among chil dren, researchers understand that they are making a similar probability statement that-all other things being equal-a given pattern of influences will increase or decrease the probability of a later harmful outcome.The variations in antisocial symp toms found in adult alcoholics offer a potentially powerful framework (i.e., construct) on which to base future subtypes.A collaborative group of researchers from three Michigan uni versities have been working to further evaluate and refine this construct.The goal of this research effort is to better define the variations in symptoms found in individual adult alcoholics and to de lineate the differences that exist among the families (i.e., familial variations).The hypothesis guiding this research is that these familial variations will in fluence the likelihood that the children from these families will develop alco hol problems or alcoholism later in their lives.

THE MICHIGAN STATE U NIVERSITYUNIVERSITY OF M ICHIGAN LONGITUDINAL STUDY
The Michigan State University University of Michigan (MSU-UM) Longitudinal Study (Zucker l987;Fitz gerald et al. l995) began as a pilot study in l982, and researchers began regular data collection in l985.The MSU-UM study was set up according to a high risk design structure (see sidebar), and it is tracking highrisk families that in clude a heterogeneous group of 220 alcoholic men, their initially preschool age (i.e., 3 to 5 years old) sons, and the boys' biological mothers.The plan is to continue the study well into the chil dren's adulthood.When the study began, the mothers' drinking status ranged from alcoholic to nondrinker.Families were excluded from partici pating, however, if the child displayed signs of fetal alcohol effects.Mothers and fathers had to be living together at the beginning of the study; however, as is common in alcoholic families, sep aration and divorce occurred at high rates.Even in such cases, the study continues to follow both biological parents.If a custodial parent has re married, the custodial stepparent is added to the study.In addition to this highrisk group, the study includes a contrast group of 91 families with sim ilar structures located in the same neigh borhoods as the highrisk families; however, in these families, both par ents were free of alcoholism and other drug (AOD) dependence.
Boys initially were selected as the target group because in the general population alcoholism is approxi mately five times more common in men than in women.In addition, sons of alcoholic fathers are about 1.5 times more likely to develop alcoholism than the offspring of nonalcoholics (Russell l990).A parallel study tracking the risk for alcoholism among girls would re

Antisocial symptoms offer a potentially powerful framework on which to base future subtypes
quire a much greater number of sub jects and, consequently, a much more expensive design.Nonetheless, the out come for girls from alcoholic homes is an equally important area of investi gation, given the broad range of other difficulties that female children of alco holics (COA's) experience (Cloninger et al. l986;Goodwin et al. l977;Widom l993).An addition to the study has al lowed the project to include one daugh ter from each of the families studied in cases where this option is available.It is still too early, however, to evaluate the data obtained from these girls.
Families are assessed at 3year in tervals.Although the study has contin ued for more than a decade, all parents but one continue to participate, includ ing those who have moved away from the study's primary field site. 3At each time point, or wave, of data collection, family members participate in a nine session schedule in which an extensive set of measures is used.These meas ures include interviews; selfreport questionnaires; reports by collateral informants, such as spouses, parents, and teachers, as well as the children's reports of their experiences with their parents; observer ratings; and data ob tained from videotaped interactions.Some research is conducted at the uni versity laboratory, but most data are collected in the respondents' homes to ensure cooperation from a study population that is known for its way wardness and chaos.Data collectors do not know the families' risk status.

EARLY RESULTS FROM THE MSU-UM LONGITUDINAL STUDY
Although the study's ultimate outcome can be determined only after the chil dren reach adulthood, a number of in fluencing structures are likely to play a role in shaping the development of alcoholism.These influences include differences in genetic vulnerability; 4 rearing environment variations; cul tural, community, and socioeconomic influences associated with risk for al coholism (i.e., macrolevel environ mental factors); and, most important, the child's personal characteristics that may put him or her at risk for an alcoholic outcome.To assess these in fluences, the study uses a number of measures that are proxy indicators of risk load.So far, the indicators being used are measures of externalizing be haviors (e.g., aggression, hyperactiv ity, and delinquency) because these characteristics are known to be pre cursors to antisocial deviance, which, in turn, has repeatedly been shown to be a precursor to the development of AOD abuse in adolescence (see Kandel l978).
3 In 1 percent of the families, a parent has died.When the study began, the researchers expected some attri tion because of a lack of interest and an inability to locate families.However, the skill of the project's clinically trained research staff and the regular contact through newsletters and birthday and Christmas cards have allowed the study to sustain this high level of family involvement.

4
The term "genetic vulnerability" specifically describes the measurement of particular genetic attributes.

Early Risk Variation Among the Families
Using data from the MSU-UM study's initial assessment period (i.e., when the children were ages 3 to 5), a series of analyses evaluated differences in the home rearing environments and in the presence and extent of externalizing behavior in the children from the alco holic (i.e., highrisk) versus the nonal coholic (i.e., lowrisk) families.These analyses demonstrated a number of significant differences between the high and lowrisk groups, as follows: • Alcoholic parents exhibited greater levels of psychopathology (e.g., de pression and antisocial symptoma tology) than nonalcoholic parents.
• The quality of the home rearing en vironment, as assessed by an inter view and observation measure of the cognitive, social, and emotional stimulation available to the child, was poorer in the highrisk than in the lowrisk families (Fitzgerald et al. l993;Noll et al. l992;Whipple et al. l995).
• Although both groups were recruited from the same neighborhoods, high risk families were lower on indices of social functioning and access to societal opportunities than were the lowrisk families (i.e., the highrisk parents were of a lower socioeco nomic status and had less educa tion) (Fitzgerald and Zucker l995).
• COA's demonstrated higher levels of externalizing behavior than non COA's and were more likely to exhibit the difficult temperament characteristics (e.g., high activity level) that Tarter and colleagues (l995) hypothesized were precursors to later alcoholic outcome (Jansen et al. l995).
• Although they were still preschool ers, the COA's could more readily identify alcoholic beverages.They also were more likely to expect male adults to choose alcoholic drinks as the beverages of choice in everyday social situations.These findings show that the COA's have a more developed cognitive structure con cerning alcoholic beverages.Thus, despite their young age, the two groups of children already differed in their rudimentary alcohol expect ancy structure (Zucker et al. l995a).

SUBTYPING OF ALCOHOLIC FAMILIES
As previously described, significant differences were found between the high and lowrisk families.The study's interest in identifying different patterns of risk variation led the investigators to explore whether risk aggregation might be even more concentrated if the par ents' alcoholism were subtyped.The subtyping scheme used was a classifi cation based on the presence or absence of differences in each father's antisocial behavior in conjunction with his alcohol ism.Theory based on the developmental psychopathology literature (see Cicchetti and Cohen l995) indicates that family risk should be greatest when the parent's psychopathological risk structure has been in place for most of his or her life time.On these grounds, and given the investigators' interest in the role of par ents' antisocial behavior, a special varia tion (i.e., a developmental stipulation) was added: The distinction between sub groups had to be made not on the basis of an ASPD diagnosis but on the basis of the presence or absence of a sustained, highlevel history of antisocial behavior during both childhood and adulthood.
Men with a pattern of alcoholism in adulthood and a sustained lifetime his tory of high antisocial behavior were categorized as antisocial alcoholics (AAL's).Those without such a sus tained history were classified as non antisocial alcoholics (NAAL's).
Although this subtyping approach is similar to one based on an adult di agnosis of ASPD, it approaches the problem developmentally.It also takes into account a theory concerning the processes involved in the acquisition of alcohol abusedependence with this particular type of comorbidity pattern.
A long history of research on the de velopment of drinking problems has noted the occurrence of a variety of other forms of deviant behavior, in cluding rule breaking, trouble making, and antisocial problem behavior, along with the drinking (Zucker et al. l995b;Zucker et al. in press).In fact, this con nection has been a central part of the dominant theories on the development of problem drinking behavior in ado lescence (Kandel l978).What is less well known is that for a subset of ado lescents, this pattern begins substan tially before adolescence and appears to continue into early adulthood and beyond.For another subset of youth, the pattern begins in adolescence but ends with the transition to adulthood, work roles, and marriage (see Zucker et al. l995b for an extensive discus sion of this literature). 5 If it is effective, the AAL-NAAL subtyping strategy should reflect dif ferences in the fathers' lifetime AOD use (i.e., early and sustained involve ment versus later onset and more tran sitory involvement).The AAL-NAAL subtypes also should serve as a marker for a variety of other influences that have shaped the early learning of the fathers' alcoholseeking and alcohol using behavior.Thus, it would be ex pected that the AAL's, more often than the NAAL's, come from families with dense family histories of alcoholism 5 The same two identifiably different lifecourse paths (i.e., trajectories) also have been noted in literature on the development of antisocial behavior (Moffitt 1993) and have given rise to a parallel taxonomy of subtypes with different onsets, life trajectories, and correlates.and have been reared in environments that encouraged or caused them to seek the company of early AODusing peers (Pihl and Peterson l994; Johnson et al. l995).If this typing strategy works, it also may prove useful as a marker of the different parenting activities of these men and their partners, which then may help to identify variations in their chil dren's risk for later alcohol problems.
The AAL-NAAL classification, based solely on the father's alcoholism, was used to chart individual and famil ial characteristics pertaining to alcohol use and familial and social functioning.The classification strategy produced findings that largely were as predicted.Other derivative findings also emerged that supported the scheme's validity.The analyses indicated that the scheme sorted out differences among the par ents that likely will serve as markers of differing vulnerability for the chil dren (see table 1).Moreover, the AAL's and NAAL's differed on several meas ures of the rearing environment that are apt to have an effect on the chil dren's socialization (see table 2).For example, the AAL men had denser family histories of alcoholism, lower levels of intellectual functioning, 6 and significantly higher levels of nonalco holic psychopathology than did the NAAL men (Bingham et al. l996;Ellis l994;Ichiyama et al. in press;Zucker et al. 1994;Zucker et al. in press).In addition, results provided evidence for the aggregation of risk by way of assortative mating 7 among the AAL families.For example, the wives of AAL men had higher levels of antiso cial behavior than did the wives of NAAL or control men.The AAL wives also had more nonantisocial psycho pathology and higher lifetime levels of alcoholrelated problems than did the wives of the control men, although they did not differ on these character istics from the NAAL wives.Finally, the AAL parents displayed more ag gressive behavior and conflict and were lower in socioeconomic status than were the NAAL and control families.
Other analyses have shown that this is a result of downward social mobility rather than differences in social origin 6 The manner in which parental IQ differences contri bute to a child's risk is less obvious than for some of the other variables described here.However, lower IQ is related to the use of less reasoned and more authori tarian forms of child discipline and lesser parent agree ment about child rearing and also may be related to specific differences in childrearing practices, such as deficits in monitoring, that ultimately may contribute to the development of antisocial behavior in the child (Davies et al. 1989).Lower IQ also may be a lowlevel indicator of neural regulatory deficits that may be a part of the genetic predisposition that contributes to the nonalcoholspecific differences in impulsivity noted among COA's (Martin et al. 1994). 7Assortative mating is the nonrandom choice of a partner based on personal characteristics (e.g., an alcoholic is more likely than a nonalcoholic to have an alcoholic partner).
between the AAL's and the NAAL's (Zucker et al. in press).
Although the pattern of these find ings is of considerable interest, concerns among scientists who have debated subtype issues focus on three vital ques tions.First, given that the two alcoholic types differ in level of antisocial be havior, what evidence exists that these differences are particular to the alco holism?To answer this question one needs to determine if a sustained anti social lifecourse subtype also exists among nonalcoholic populations.Cur rent evidence indicates that this is high ly unlikely, at least in this culture; because the link between antisocial behavior and alcoholism is so close, sustained antisocial behavior among nonalcoholics statistically is a rare occurrence (Zucker et al. in press).
Second, because the AAL's and the NAAL's differ in their levels of sustained antisocial behavior, is it more parsimonious to regard the high and low levels of antisocial behavior as extremes on a continuum, rather than as distinct types with similar (i.e., clustered) attributes?Several types of analysis, using sophisticated statistical techniques, have focused on this issue, including one analytic technique called configural cluster analysis (Zucker et al. in press) and another called struc tural equation modeling (Ellis 1994;Zucker et al. 1994), discussed below.
Results from the configural cluster analysis indicate that in addition to the close link between antisocial charac teristics and alcoholism, one other distinct clustering, or type, is present.This type, called the nonantisocial al coholic group, involves the coaggre gation of alcoholism and a lifetime of continuous, lowlevel antisocial be havior.In other words, a pattern of continuous, highlevel antisocial be havior is found in association with alcoholism; a pattern of continuous, lowlevel antisocial behavior is linked to the absence of alcoholism; and a third pattern, alcoholic coaggregation, also has been observed, in which low level antisocial behavior is clustered with alcoholism.
Third, nonantisocial psychopathol ogy as well as antisocial behavior varies across the two alcoholic subtypes.On these grounds, what evidence exists that the AAL-NAAL classification primarily involves higher versus lower levels of antisocial behavior, rather than variations in general psychopatho logy that occur over the life course?This is a central issue, because one of the major alcoholism subtyping schemes currently in use, the type Atype B categorization (Babor et al. l992), is a framework that heavily categorizes alcoholism based on the level of psy chopathology.To test this competing hypothesis, statistical analyses were conducted that removed the effects of general level/severity of psychopatho logy (Ichiyama et al. in press; Zucker et al. in press).The results still held, confirming the unique importance of the antisocial categorization.

OUTCOMES AMONG THE CHILDREN OF DIFFERENT ALCOHOLIC SUBTYPES
The findings described in the pre vious section focus on parents in al coholic families.These findings are To date, the study has collected data on the chil dren and their families from two age periods: during preschool (i.e., ages 3 to 5) and during the early school years (i.e., ages 6 to 8).
Results show that during both early childhood and the early school years, significant behavioral differences exist between the children from families with different alcoholic subtypes (table 3) Bingham et al. l996;Ellis 1994, Zucker et al. 1994).For example, externalizing behaviors, the foremost proxy indicator of the emergence of earlier and more problematic adolescent alcohol use, and internalizing behaviors are great est among the children of AAL's at both assessment periods.In addition, as preschoolers, the AAL boys showed more signs of hyperactivity and scored higher on a measure of risky tempera ment than did the boys from the NAAL and control families.Other analyses indicate that these differences exist not only in the level of overall group effects but in extremes of behavior.That is, significantly more boys from AAL homes than from the NAAL or control homes were classified in the clinical range on externalizing behavior problems (Jansen et al. l995;Ellis 1994;Zucker et al. 1994).Finally, using a technique called structural equation modeling, researchers have found that separate process models for the AAL's, NAAL's, and control families better describe the interrelationships among the different variables than does one overall model.This finding implies that the pathways of influencing struc ture differ among the three groups and tentatively suggests that the mechanisms of risk development may be specific to subtypes.The latter finding has only been established at the first wave of data collection and will need to be rep licated in later longitudinal analyses.

THE BROADER STRUCTURE OF RISK: CONCLUSIONS AND OUTLOOK
The typological classification described in this article and the derivative find ings from the ongoing longitudinal study highlight observations from other investigators (e.g., Jacob and Leonard l986), which indicate that not all alco holic families are equally problematic and not all COA's function in a manner that distinguishes them from nonalco holic families or is indicative of a po tentially troubled later outcome.For example, some elements of family func tioning that are thought to be associated with alcoholism (e.g., aggression with in the family) appear to be manifesta tions of only one subtype (i.e., AAL's).Similarly, not all COA's exhibit be haviors that differ from those of non COA's.Children from NAAL families occupy this intermediary position.From a practical standpoint, findings to date have indicated that NAAL families often are less identifiable as sources of developmental trouble, and the risk differences observed emphasize the possibility that NAAL children will be less at risk as they move into ado lescence.The ability of researchers to determine more finely detailed and subtle differentiations within the alco holic disorder is one aspect of the use fulness of subtyping.
The findings summarized here, which involved determining the fami lies' alcoholism subtypes as well as showing significant differences in childhood risk patterns related to the subtypes, were determined when the children were ages 3 to 5. It would be a serious mistake to conclude that all effects of subtyping and problematic outcome have appeared by the time these atrisk children have reached middle childhood.Evidence continues to indicate that both school and later peer influences play important roles in shaping a child's risk status (Johnson et al. l995); moreover, later positive or negative parental influences probably continue to sustain or alleviate child risk (Wills et al. l996).Not all alco holics remain actively alcoholic, and it is possible that the family subtype classifications used here will evolve over the course of childhood.More over, parents in alcoholic families frequently divorce, and new family structures may be formed that shape a child's behavior in different ways from when he or she was young.This is a probabilistic framework for viewing how risk increases and decreases over time.It is important to keep this frame work in mind, even as we discover that not all family structures carry the same risk burden.
At the same time, risk variation within subtypes is not random over time (Bingham et al,l996), and the contextual structure that sustains and may even enhance an individual's risk does not vary randomly either (Zucker et al. l995b).Some social environments heavily restrict the range of opportunity; and, within these contexts, risk appears to be more heavily aggregated.Such restricted environments include poverty areas, frequently inhabited by disen franchised minorities.The term "nest ing environment" has been used to describe this restricted range of op portunity and the nonrandom aggre gation of factors (i.e., nesting) that sustain individual risk.Under condi tions of nestedness, when environment and biological risk coincide, subtypes are most likely to develop (also see Wills et al. 1996).
Two additional features of this re search warrant some comment.First, not all aspects of early childhood func tioning varied with familial subtype.For example, although preschool chil dren from alcoholic families were more precocious in their ability to identify alcoholic beverages and exhibited a more highly developed conceptual un derstanding about alcohol as a drug, its effects, and who should use it, the subtype differences in the children's development of these schemes were not evident (Zucker et al. l995a).This finding was unexpected, given the earlier onset of drinking and drinking problems among adult AAL's.It re mains to be seen whether subtype dif ferentiation will appear as the children grow older.
Second, the research carried out thus far has been guided by the proposition that one alcoholic subtype, marked by the sustained lifecourse presence of antisocial behavior, would differ from other forms of alcoholism in lifecourse functioning, in the rearing environment available to the offspring, and in child hood characteristics indicative of level of risk for later alcohol problems.Con trasts have been made against a hetero geneous group of other alcoholic families (NAAL's), who in some re spects are even indistinguishable from nonalcoholic families.Given the vari ety of other comorbid symptoms found among alcoholics in the general popu lation, other subtypes may exist that display different distinguishing char acteristics and which create different rearing and risk environments for their children.The comorbidity literature suggests that these characteristics may exist (Helzer et al. l991;Zucker l994), but other variants (e.g., alcoholism without comorbidity and developmen tally limited alcoholism) have received much less attention in the typological literature.Accordingly, future research needs to better characterize these other variations among both fathers and mothers and to assess their influences on the development of risk among the children.Finally, researchers must de termine the extent to which the effects of parental alcoholism subtype on the risk status of male COA's can be gen eralized to female children from the same families.■ Alcoholism risk factors illustrated in "The Bottle," 1847, by George Cruikshank.Re produced with permission from the Journal of Studies on Alcohol.© Alcohol Research Documentation, Inc., Rutgers University Cen ter of Alcohol Studies.

Table 1
Differences Among Families With Different Alcoholic Subtypes and Nonalco holic Controls in Indicators of the Offspring's Early Vulnerability for Alcoholism 1 Matched nonalcoholics recruited from the same communities.SOURCE: Adapted fromEllis et al. 1994 and Zucker et al. in press.

Table 2
Differences in Indicators of the Early Rearing Environment of Children From Families With Different Alcoholic Subtypes and From Nonalcoholic Control Families 1

Table 3
Differences in Childhood Risk Indicators Among Boys From Families With Different Alcoholic Subtypes and From Nonalcoholic Control Families